I just purchased a new 2019 Studio, and was curious to find this post. The bridge on mine also has the white washers.
Before pulling the trigger on this purchase, I reviewed the specs on the Gibson website (about 2weeks ago) and they made a big deal about using the ABR-1 bridge. I printed the spec page for my records, and I’m glad I did because Gibson no longer has the Studio page on their web site. Maybe they pulled it because of GuitarGene’s inquiry?